The aim of our research is to improve the diagnostic quality of radiographic images for cancer diagnosis and to minimize the patient exposure incurred during the radiographic examination. Our plan includes (1) application of magnification radiography with an ultra high speed rare-earth recording system to chest radiography for the characterization of pulmonary masses (and to distinguish benign from malignant); (2) in bone radiography, development of a high speed and high resolution technique for skeletal radiography to identify bone metastases and to assess disease progression; and (3) evaluation of new stereoscopic techniques for accurate diagnosis of brain tumors. Clinical results will be analyzed by a group of radiologists in blind studies or side-by-side comparisons of radiographs, in order to establish statistically the usefulness of the new techniques applied to various examinations. The technical approach to applied and clinical studies of radiographic imaging described above is based on the application of methods of optical communication theory to the analysis of factors affecting detail visibility of radiographic images. This involves (1) x-ray energy spectral analysis to study the relationship among the beam quality, patient exposure and image quality; (2) sensitometric evaluation of recording systems; (3) evaluation of modulation transfer functions to provide transfer characteristics of recording systems and of geometric unsharpness; (4) investigation of radiographic mottle to determine the effect of noise on detail visibilities of low contrast radiologic objects; (5) computer simulation studies to optimize the physical parameters discussed above, and (6) ROC analysis of observer performance in detecting simple test object images and in evaluating diagnostic accuracies of bone radiography.